Quaternary ammonium compounds

ABSTRACT

QUATERNARY AMMONIUM IMIDES HAVING SURFACE-ACTIVE PROPERTIES ARE DESCRIBED. THE IMIDES ARE ABLE TO EXIST IN ZWITTERIONIC OR CATIONIC FORM AND THUS FIND APPLICABILITY IN THE TREATMENT OF TEXTILES AND HARD SURFACES. SURFACE TREATING COMPOSITIONS CONTAINING QUATERNARY AMMMONIUM IMIDE AND A PH BUFFERING COMPOUND ARE DESCRIBED. ALSO DESCRIBED ARE METHODS FOR TREATING FABRICS AND HARD SURFACES.

US. Cl. 260-295 Q 8 Claims ABSTRACT OF THE DISCLOSURE Quaternary ammonium imides having surface-active properties are described. The imides are able to exist in zwitterionic or cationic form and thus find applicability in the treatment of textiles and hard surfaces. Surface treating compositions containing quaternary ammonium imide and a pH buffering compound are described. Also described are methods for treating fabrics and hard surfaces.

BACKGROUND OF THE INVENTION The invention relates to new quaternary ammonium imides which are surface active agents, and are able to exist in zwitterionic or in cationic form.

Quaternary ammonium compounds having at least one long chain (about C upwards) hydrophobic radical in the molecule have long been known. They are useful as cationic surface-active agents (so called invert soaps), as textile softening agents and as bactericides. When intended for use as textile softeners, long-chained compounds, for instance having about 16 to 22 or more carbon atoms, are preferred, especially compounds with two long chain groups. Typical examples include: octadecyldimethyl benzyl ammonium chloride, octadecyltrimethyl ammonium chloride, distearyl dimethyl ammoniurn chloride, the corresponding bromides, and many others of similar structure.

These compounds, particularly distearyl dimethyl ammonium chloride, have been used commercially in textile softening compositions intended to be added to the last rinse water after a conventional washing process, and attempts have been made to use them in detergent compositions intended to be combined washing and textile softening agents.

Being cationic, these substances ordinarily react with anionic detergents to form insoluble substances, and so their use in the presence of anionic detergents is not normally practicable. Furthermore, they have a strong affinity for fabrics, especially cotton and wools, a fact which plays an important part in their effectiveness as textile softeners and bactericides, but also has the effect that they are generally not completely washed out of the fabric in a succeeding wash. They therefore tend to build up on repeatedly washed fabrics, and may thus impair the re-wetting properties of the fabrics, tend to cause discoloration, fiber snagging and even cause undesirable odors. Such fabrics, though soft, often have an unpleasant greasy feel after several treatments. A similar effect is observed on hard surfaces. Thus, when cationic surface-active agents are used as sterilizing agents in dishor glass-Washing, a hydrophobic layer remains adsorbed on the surface, which when re-wetted, has a greasy appearance.

Other quaternary ammonium compounds constitute the known zwitterionic surface-active compounds, for example, the long-chain carboxylic betaines, sulphobetaines, sulphato and sulphito betaines. These compounds are valuable wetting agents and detergents. As

at f

they are internal salts, and therefore do not react with the metal ions present in hard water, especially calcium ions, they are almost unaffected by water hardness. For the same reason, they are compatible with anionic, cationic and nonionic detergents. Their affinity for and wetting effect upon certain highly hydrophobic fibers, such as polyamine and polyester fibers, renders them particularly valuable for removing certain types of soils, especially greasy soils, from these materials. They are also remarkably effective in cleaning cotton fabrics soiled with dirt containing clay particles. However. they are not strongly substantive to fabrics and are not very effective textile softening agents. These known betaine and betaine-like compounds exist in zwitterionic form over a wide range of pH. In relatively strongly acid conditions they do become cationic, but the necessary acidity is outside the practical range for washing fabrics or human beings.

The present invention is concerned with a class of surface-active agents which are cationic under weakly acid conditions, and are zwitterionic under weakly alkaline conditions, the acidity or alkalinity being relative to their pKa value as defined hereinafter. Thus, if present at the ordinary pH of a rinsing operation in an aqueous solution (which need not necessarily constitute the rinse after a wash) they are largely in cationic form and are effective as textile softening agents substantive to fabrics. Under the ordinarily alkaline conditions of a subsequent conventional washing operation, they convert to zwitterionic form, and thus are non-substantive to the fabrics, In this form they are compatible with the detergent composition.

Both on textile fibers and on other surfaces, for exam ple hard surfaces, the adsorbed cationic and/or zwitterionic layer provides a surface which tends to repel important classes of soil (or dirt) and to promote their separation from the surface and their dispersion in a subsequent alkaline wash, when the adsorbed layer is rendered non-substantive. Thus these substances can act as soil-release agents which are removed at each wash, and can be re-applied in a rinse or like treatment before the surface is re-exposed to soiling. They may also impart anti-static and bactericidal properties to the surfaces treat-ed with them, and some of these substances act to inhibit the transfer of dyes from one article or part of an article to another in washing solutions and the like.

SUMMARY OF THE INVENTION According to the invention, there are provided quaternary ammonium imides having the formula R2 R 0 ON-C 0 CH2N R3 or their cationic adducts having the formula R2 R1CONHCOCH2NR3 wherein X is an anion;

R is an alkyl of from 1 to 25 carbon atoms, phenyl, benzyl, alkylphenyl where the alkyl has from 8 to 18 carbon atoms, or alkylbenzyl where the alkyl has from 8 to 18 carbon atoms;

R is an alkyl of from 1 to 26 carbonatoms, or phenyl; each of R and R is an alkyl of from 1 to 4 carbon atoms, phenyl or benzyl, or R R and R together represent a pyridine ring; and one or both of R and R contain at least 10 carbon atoms,

In its composition aspect, the present invention provides surface-treating compositions comprising a quaternary ammonium imide, as defined hereinbefore and having a pKa value in the range of 7 to and a pH buffering compound. In its process or method aspect, the present invention provides a method of treating fabric materials whereby the fabrics are improved in softness without undesirable build-up with succeeding washing treat ments which comprises the steps of treating the fabrics with a solution of a predominantly cationic and fabricsubstantive compound described hereinbefore thereby to improve softness and, thereafter, Washing the fabrics under alkaline conditions to remove the softener in a pre dominantly zwitterionic form. Also provided is a method of treating hard surfaces whereby the predominantly cationic and substantive form is applied to hard surfaces, said surfaces are subjected to soiling effects and the cationic form is substantially removed by altering the pH of the treated surface to effect conversion to a predominantly zwitterionic form.

DETAILED DESCRIPTION OF THE INVENTION The quaternary ammonium imides of the invention can be conveniently prepared. For example, they can be prepared by reaction of chloracetyl chloride with an amide of formula:

R CONH and reacting the resulting product with a tertiary amine NR R R the Rs having the definitions hereinbefore ascribed.

Particularly advantageous compounds of the invention are those of the above-mentioned formula in which R is an alkylbenzyl group having 12 to 14 carbon atoms in the alkyl group or an alkyl group having from 13 to 21 carbon atoms and wherein R R and R are each a methyl or ethyl group or a phenyl or benzyl group or together constitute a pyridine ring. Especially preferred compounds are those where R R and R each represents a methyl group. Other suitable compounds are those of the above formula in which each of R R and R represents a short-chain group, either alkyl having 1 to 6 carbon atoms or phenyl or benzyl, and R is a long-chain alkyl group having from 10 to 26, preferably 14 to 22 carbon atoms. Preferably in these compounds R is methyl or ethyl, especially methyl. Yet other suitable compounds are those wherein both R and R which need not be the same, are long-chain groups as defined above.

As indicated above, the compounds to be surface-active agents must have at least one long-chain hydrophobic group and they may have two such groups. Usually, in preparing the compounds, it is preferred to start with a long-chain amide, for instance a fatty acyl amide having from about 10 to 26 carbon atoms, preferably 14 to 22 carbon atoms, derived from fats or other sources of high molecular weight fatty acids, or an alkylbenzyl or alkylphenyl amide having about 8 to 18, preferably about 12 to 14 carbon atoms in the alkyl chain.

In particular, the amide may be derived from a typical detergent alkylate, via the corresponding alkylbenzyl chloride.

The tertiary amine may act as the source of a longchain hydrophobic group, in which case it may contain a long-chain alkyl group as described above. The remaining groups are normally short-chain groups, such as methyl, ethyl or they may be benzyl or phenyl groups. Alternatively R R and K; may together represent a heterocyclic ring such as a pyridine ring. The preferred tertiary amine is trimethyl amine.

The anion X, in the ammonium imides of the invention in their cationic form, may be any convenient anion, for example halide (e.g., chloride or bromide), sulfate or methosulphate. Other anions include bisulfate, nitrate, perchlorate and fiuoroborate. Often, the anion is the anion of a buffering agent with which the ammonium imide is associated in a composition, as described hereinafter.

In aqueous solution, and when separated from aqueous solution, the imides of the invention can exist either 1n cationic form at relatively low pH or in zwitterionic form at relatively high pH and they have pKa value in the range 7-10, usually 8 to 8.5. The pKa value is the pH at which the compounds are 50 molar percent in zwitterionic and 50 molar percent in cationic form. Thus at a lower pH they are predominantly cationic and at a high pH predominantly zwitterionic, but at pH near the pKa value both forms may be present to a considerable extent.

The invention also provides novel surface treating compositions comprising one or more conventional components of such compositions and a quaternary ammonium imide as defined above, said imide having pKa value in the range 7 to 10.

These compositions are useful as textile softening agents, which do not build up upon and do not impair the re-wettability of textiles treated repeatedly with them, and do not cause discoloration or greasiness of the textiles. Furthermore, they act as soil-repellent and/or soil-release agents, so that soiled surfaces of textiles and other materials are more easily cleaned in subsequent washing, particularly in less than ideal washing conditions, for instance when Washing at relatively low temperature (below 60 C.) and/or when using a lower than optimum concentration of a conventional household detergent composition. They are particularly valuable in aiding removal of greasy and greasy-particulate soils and claybased soils from textiles and from hard surfaces.

Often, it is convenient to apply the compositions of the invention at some stage during a washing process, for instance at the rinse stage, and they may constitute what are known as rinse additives. Here, it will be understood that the first so called rinse of a new article might well take place before it is first washed or even used, to provide soil-release properties and other benefits. Preferably, the compositions contain pH buffering agents, of a type and in amount such that an aqueous solution of the composition, for instance in tap water or in a rinse solution after a conventional, generally alkaline wash, has a pH near or below the pKa value of the surface active agent, so that it is present to a considerable degree in cationic form.

The compositions are especially effective if buffered so that the pH of the solution is close to the said pKa value, for example within two pH units above or below it, especially within about 1 unit. Preferably, sufiicient buflering agent is employed as to cause a solution having 0.1% of the imide in cationic form to have a pH which is below the pKa value of the imide. Any effective buffering agent can be used, which is effective at the desired pH, for instance phosphates, polyphosphates, borates, salts of weak organic acids, such as citric, lactic, glycolic, malic, tartaric, acetic, capric, benzoic or adipic, the corresponding acids and mixtures of any of these. Preferred buffering agents are the alkali metal (e.g. sodium and potassium) phosphates, polyphosphates, borates and citrates.

The proportions of components in such compositions depend upon the way in which the compositions are intended to be employed, and upon the nature of the components selected. Suitably the amount of cationic form of the surface active agent present may be in the range about 0.01% to 0.5% by dry weight of a fabric to be treated, for example at about 0.1%.

On another basis, effective rinse additive compositions have contained about 1 to 20%, for example about 5% by weight of cationic form of the surface active agent, and have been used at a concentration of about 0.2 to 0.5 by Weight in a treating solution, but these figures are not to be considered limiting.

The compositions of the invention may, alternatively, be formulated as alkaline detergent compositions, taking advantage of the valuable detergent properties of the zwitterionic form of the imides of the invention. Such compositions can contain the usual alkaline detergency building salts and sequestering agents, and may contain other non-cationic surface active agents. When diluted with tap Water or the like in a rinse step to reduce the pH to near or below the pKa value, the proportion of the imide of the invention which remains becomes to a considerable degree cationic and substantive to the surface being washed, with the advantages described above. Usually, such built detergent compositions contain detergency builder salts and total organic surface active agent in a weight ratio in the range from about 1:4 to 30: 1.

Another way of using the compositions as textile softeners is to formulate them as presoak compositions. Thus fabrics which are to be washed are given a preliminary soaking or wetting in an aqueous solution containing the cationic form of a compound of the invention. Thereafter a conventional detergent composition may be added to the same solution and washing and rinsing carried out normally. Alternatively the surplus solution may be separated from the fabrics, for instance by spin drying, and then they can be washed and rinsed in the ordinary way.

These presoak compositions need only contain the compound of the invention, but normally they contain also a diluent or carrier medium. Often it is useful to include another zwitterionic or nonionic surface active agent to improve the solubility of the quaternary ammonium imide.

The compositions described above whether alkaline or not, may contain compatible components of conventional compositions of the class to which they belong. Thus the alkaline detergent compositions may contain builders as mentioned above, for instance water-soluble, usually alkali metal, especially sodium or potassium, phosphates and polyphosphates, carbonates, silicates, etc., and chelating agents such as nitrilotriacetates, polycarboxylates, such as those described in U.S. Pat. 3,308,067 (Mar. 7, 1967) and citrates, gluconates and the like. Neutral salts such as alkali metal chlorides and sulphates may also be present, also bleaching agents such as sodium perborate, percarbonates and perphosphates. Minor components that may also be present include: suds controlling agents, enzymes, activators or stabilizers for enzymes and/ or for the bleaching agents, dust inhibitors, etc. Compositions of either sort may contain chelating agents effective at the appropriate pH level, optical brighteners, perfume, color matters, and, if the compositions are liquid, emulsifying agents, hydrotropes, solvents and the like. As will be understood, some of these components may have more than one function, for instance as both buffering and chelating agents.

In the alkaline detergent compositions, the quarternary ammonium imides in non-cationic form are compatible with other surfactants of any class.

In the compositions wherein the imide is in cationic form, anionic detergents are preferably absent. Suitable anionic detergents, when compatible, include the sulphonic and sulphuric acid derivatives such as alkyl aryl sulphonates, alkyl sulphates, alkyl ether sulphates, and many others well known in the art. Suitable nonionic detergents include polyethoxy alcohols, alkyl phenols, fatty acids, amines and the like, polyethoxy polypropylene oxide condensates, polyethoxy sorbitan esters, and many others. Suitable zwitterionics include: quaternary ammonuim carboxylates (betaines) sulphonates (sulpho betaines) and the like, some of which have been mentioned above. Semi-polar nonionic surfactants such as tertiary amine oxides or phosphine-oxides may also be present. Other examples of suitable detergents are provided in US. Pat. 3,213,030, issued Oct. 19, 1965, lines 5375 of column 3, lines 1 to 75 of column 4 and lines 1 to 30 of column 5, which disclosure is incorporated herein by reference. Normally, the built detergent compositions of the invention will comprise the ammonioamidate of the invention in an amount of 1% to 20%, preferably to The following examples illustrate the invention:

6 EXAMPLE I Commercial linear dodecyl benzene was converted to the dodecylbenzylchloride and then, via the corresponding nitrile, to dodecylphenylacetamide. The orthoand para-isomers were present in ratio of about 1:4.

3.4 g. of dodecylphenylacetamide and 15 ml. of chloracetyl chloride were heated under reflux for 2 hours. Excess chloracetyl chloride was removed by evaporation under reduced pressure, and the residue was dissolved in acetone (50 ml.). A large excess of gaseous trimethylamine was passed into this solution during one hour and then the mixture was allowed to stand for 16 hours before filtering off the brown, crystalline product (1). The reaction can be represented thus:

l MeaN Infra-red examination of the product indicated that it was contaminated with trimethyl ammonium chloride; it was purified by passing a methanolic solution of the crude product through a column of hydroxyl ion exchange resin (50 ml. IR 400A). Evaporation of the eluant gave purified product in the zwitterionic form (2).

o mrn5-omc o 1 1 o o c H l lMe This substance in the conjugate acid form (1) has a pKa value of -8.5.

EXAMPLE II wherein R was n-dodecyl, the pH of the solution being adjusted to 6.5. The pKa value of this compound was 8.3. The swatches were rinsed in tap water and dried.

Both groups of swatches were then soiled uniformly with an aqueous slurry of ground garden earth, constituting a clay-type soil, and dried. Each group of swatches was then washed in a 0.2% solution of the same heavy duty detergent at 60 C. for 5 minutes, rinsed in tap water and dried. The solution had a pH of 10.

The swatches of group (b) were visibly cleaner than those of group (a).

EXAMPLE III A cotton swatch was immersed for 3 minutes in a 1% solution in tap water of the compound (3) of Example II. The pH of the solution was 4.2. It was then rinsed in water and dried. A comparative swatch was immersed in water and dried. The swatches were then immersed in an aqueous dispersion containing parts per million by weight of the dyestuif Chlorarnine Rose B. (Color Index: Direct Red 31). The swatches were rinsed and dried. The swatch that was pro-treated in the solution of the compound of the invention was seen to be less colored than that pre-treated in water only.

7 EXAMPLE IV (a) Chloroacetyloctadecanimide (b) Quaternization of Chloroacetyloctadecanimide 1) Chloroacetyloctadecanimide (1 g.) was dissolved in warm acetone (50 m1.) and trimethylamine (5 ml.) was added. Sixteen hours later, the precipitated product (1.1 g.) was filtered and thoroughly washed with acetone.

The reaction was according to the equation:

Acetone CnHasC ONHC O CHzCH-MG N 011E350 ONHC o CHZNKIOZ oi- EXAMPLEV Similarly by treating chloroacetyldodecanimide with pyridine or alkyl dimethyl amine (C H )NMe the folo lowing types were prepared:

pyridine CnHzaC ONHC 0 011201 CnHmC ONHC 0 CHzN-QCI R N M82 OnH IlCONHCOCHzCl M e 01111 ONHC 0 CHzN-MO 01 EXAMPLE VI Test pieces of cotton terry towelling were given two pre-treatment washes in a conventional heavy duty household synthetic detergent composition. (Ariel: P&G Ltd.) rinsed after each, and dried.

The test pieces were divided into two groups and one group (a) was washed in a 0.55% by weight solution of k the same conventional detergent; the other group (b) was washed in an identical solution except for the addition of 0.025% of the compound:

The solutions were made in hard water (258 ppm. as CaCO The washing was performed in a miniature washing machine. The washing conditions were:

10 minutes at 120 F.

g. of fabric per pot in the machine.

20:1 weight ratio liquor to fabric.

Two test pieces per pot, two pots per composition compared.

After the wash the fabrics were spin-dried, rinsed twice in cold hard water (10:1 ratio liquor to fabric), spindried and air dried.

They were compared by a paired comparison technique for softeness by a panel of four ladies.

The results, in panel score units (positive preferred) were:

Group (a) -0.46 Group (b) +0.52 Least significant difference 1 0.78

1 95% confidence.

8 EXAMPLE v11 Preparation of Chloroacetylacetamide Chloroacetamide (6.0 g.), acetic anhydride (9.0 g.) and acetyl chloride (0.6 ml.) were heated under reflux for 1 hour. To the cooled solution, benzene (25 mls.) was added. After 2 hours, the precipitated product was filtered, washed with light petroleum and dried. The yield was 5.7 g. and the chloroacetylacetarnide showed mp. 103- 105. (The method is adapted from that of Polya and Spotswood, Recueil 1948, 67, 927.)

Quaternization of Chloroacetylacetamide Chloroacetylamide (1 g.) and octadecyldimethylamine (2.5 g.) in acetone (10 mls.) were heated under reflux for 1.5 hours. On cooling, the quaternary ammonium imide (1) precipitated and was isolated by filtration. The yield was 2.4 g. The product was water soluble, yielded a foaming solution and gave a positive reaction for ionic chloride. The LR. spectrum was compatible with the assigned structure:

CHJCONHCOCHZI'VMOZ C1 isHar What we claim is: 1. A quaternary ammonium imide having the formula or the cationic adduct thereof having the formula wherein X is an anion selected from the group consisting of chloride and methosulfate;

R is an alkyl of from 1 to 25 carbon atoms, phenyl, benzyl, alkylphenyl where the alkyl has from 8 to 18 carbon atoms, or alkylbenzyl where the alkyl has from 8 to 18 carbon atoms;

R is an alkyl of from 1 to 26 carbon atoms, benzyl or phenyl radical;

each of R and R is an alkyl of from 1 to 4 carbon atoms, phenyl, or benzyl or R R and R together represent a pyridine ring; and one or both of R and R contains at least 10 carbon atoms.

2. A compound of Claim 1 wherein R is an alkyl of from 13 to 21 carbon atoms.

3. A compound of Claim 2, wherein each of R R and R is methyl or ethyl.

4. A compound of Claim 2 wherein R R and R together represent a pyridine ring.

5. A compound of Claim 1 wherein R is an alkyl of from 14 to 22 carbon atoms.

6. A compound of Claim 5 wherein each of R and R is methyl or ethyl.

7. A compound of Claim 1 wherein R is alkylbenzyl where the alkyl has from 12 to 14 carbon atoms.

8. A compound of Claim 7 wherein each of R R and R is methyl or ethyl.

References Cited LaRocca et al., J. Pharm. Sci. vol. 54, pp. 65455 (1969).

HARRY I. MOATZ, Primary Examiner U.S. Cl. X.R.

260501.15, 558 A, 561 A, 562 N, 404.5; 252357, 547, 106 

